Semiconductor lasers are attractive for a wide variety of applications including optical interconnection of integrated circuits, telecommunications, computing systems and optical recording systems. Semiconductor lasers provide a compact source of coherent, monochromatic light which can be modulated at high bit rates to transmit large amounts of information. Because aging and temperature changes vary the level of laser output, semiconductor lasers typically require monitoring circuits to provide dynamic stabilization of the laser output.
Unfortunately the geometry of conventional edge emitting lasers does not favor easy integration with the other components used in semiconductor laser systems. Edge emitting lasers emit coherent light along an embedded planar surface parallel to the substrate surface. Thus the lasting direction is parallel to the planes of growth in typical semiconductor processes. As a consequence, edge emitting lasers are typically fabricated and tested as discrete devices. In use edge emitting lasers are typically combined with separately fabricated modulators and photodiodes. Thus fabrication of a semiconductor laser system typically involves time-consuming assembly and alignment of plural discrete components.